/*
 *  ISO 9660 filesystem backend for GRUB (GRand Unified Bootloader)
 *  including Rock Ridge Extensions support
 *
 *  Copyright (C) 1998, 1999  Kousuke Takai  <tak@kmc.kyoto-u.ac.jp>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/*
 *  References:
 *	linux/fs/isofs/rock.[ch]
 *	mkisofs-1.11.1/diag/isoinfo.c
 *	mkisofs-1.11.1/iso9660.h
 *		(all are written by Eric Youngdale)
 *
 *  Modifications by:
 *	Leonid Lisovskiy   <lly@pisem.net>	2003
 */

#ifdef FSYS_ISO9660

#include "shared.h"
#include "filesys.h"
#include "iso9660.h"

/* iso9660 super-block data in memory */
struct iso_sb_info {
  unsigned long vol_sector;

};

/* iso fs inode data in memory */
struct iso_inode_info {
  unsigned long file_start;
};

#define ISO_SUPER	\
    ((struct iso_sb_info *)(FSYS_BUF))
#define INODE		\
    ((struct iso_inode_info *)(FSYS_BUF+sizeof(struct iso_sb_info)))
#define PRIMDESC        ((struct iso_primary_descriptor *)(FSYS_BUF + 2048))
#define DIRREC          ((struct iso_directory_record *)(FSYS_BUF + 4096))
#define RRCONT_BUF      ((unsigned char *)(FSYS_BUF + 6144))
#define NAME_BUF        ((unsigned char *)(FSYS_BUF + 8192))


static inline unsigned long
log2 (unsigned long word)
{
  asm volatile ("bsfl %1,%0"
		:          "=r" (word)
		:          "r" (word));
  return word;
}

static int
iso9660_devread (int sector, int byte_offset, int byte_len, char *buf)
{
  unsigned short sector_size_lg2 = log2(buf_geom.sector_size);

  /*
   * We have to use own devread() function since BIOS return wrong geometry
   */
  if (sector < 0)
    {
      errnum = ERR_OUTSIDE_PART;
      return 0;
    }
  if (byte_len <= 0)
    return 1;

  sector += (byte_offset >> sector_size_lg2);
  byte_offset &= (buf_geom.sector_size - 1);
  asm volatile ("shl%L0 %1,%0"
		: "=r"(sector)
		: "Ic"((int8_t)(ISO_SECTOR_BITS - sector_size_lg2)),
		"0"(sector));

#if !defined(STAGE1_5)
  if (disk_read_hook && debug)
    printf ("<%d, %d, %d>", sector, byte_offset, byte_len);
#endif /* !STAGE1_5 */

  return rawread(current_drive, part_start + sector, byte_offset, byte_len, buf);
}

int
iso9660_mount (void)
{
  unsigned int sector;

  /*
   *  Because there is no defined slice type ID for ISO-9660 filesystem,
   *  this test will pass only either (1) if entire disk is used, or
   *  (2) if current partition is BSD style sub-partition whose ID is
   *  ISO-9660.
   */
  if ((current_partition != 0xFFFFFF)
      && !IS_PC_SLICE_TYPE_BSD_WITH_FS(current_slice, FS_ISO9660))
    return 0;

  /*
   *  Currently, only FIRST session of MultiSession disks are supported !!!
   */
  for (sector = 16 ; sector < 32 ; sector++)
    {
        if (!iso9660_devread(sector, 0, sizeof(*PRIMDESC), (char *)PRIMDESC)) 
            break;

        /* check ISO_VD_PRIMARY and ISO_STANDARD_ID */
        if (PRIMDESC->type.l == ISO_VD_PRIMARY
        && !memcmp(PRIMDESC->id, ISO_STANDARD_ID, sizeof(PRIMDESC->id)))
        {
            ISO_SUPER->vol_sector = sector;
            INODE->file_start = 0;
            fsmax = PRIMDESC->volume_space_size.l;
            return 1;
        }
    }

  return 0;
}

int
iso9660_dir (char *dirname)
{
    struct iso_directory_record *idr;
    RR_ptr_t rr_ptr;
    struct rock_ridge *ce_ptr;
    unsigned int pathlen;
    int size;
    unsigned int extent;
    unsigned char file_type;
    unsigned int rr_len;
    unsigned char rr_flag;

    idr = &PRIMDESC->root_directory_record;
    INODE->file_start = 0;

    do
    {
        while (*dirname == '/')	/* skip leading slashes */
            dirname++;

        /* pathlen = strcspn(dirname, "/\n\t "); */
        for (pathlen = 0 ;
            dirname[pathlen]
            && !isspace(dirname[pathlen]) && dirname[pathlen] != '/' ;
            pathlen++)
                ;

        size = idr->size.l;
        extent = idr->extent.l;

        while (size > 0)
        {
            if (!iso9660_devread(extent, 0, ISO_SECTOR_SIZE, (char *)DIRREC))
            {
                errnum = ERR_FSYS_CORRUPT;
                return 0;
            }
            extent++;

            idr = (struct iso_directory_record *)DIRREC;

            for (; idr->length.l > 0;
                idr = (struct iso_directory_record *)((char *)idr + idr->length.l) )
            {
                const char *name = idr->name;
                unsigned int name_len = idr->name_len.l;

                file_type = (idr->flags.l & 2) ? ISO_DIRECTORY : ISO_REGULAR;
                if (name_len == 1)
                {
                    if ((name[0] == 0) ||	/* self */
                      (name[0] == 1)) 	/* parent */
                        continue;
                }

                if (name_len > 2 && CHECK2(name + name_len - 2, ';', '1'))
                {
                    name_len -= 2;	/* truncate trailing file version */
                    if (name_len > 1 && name[name_len - 1] == '.')
                    name_len--;		/* truncate trailing dot */
                }

                /*
                *  Parse Rock-Ridge extension
                */
                rr_len = (idr->length.l - idr->name_len.l
                    - sizeof(struct iso_directory_record)
                    + sizeof(idr->name));

                rr_ptr.ptr = ((unsigned char *)idr + idr->name_len.l
                    + sizeof(struct iso_directory_record)
                    - sizeof(idr->name));

                if (rr_ptr.i & 1)
                    rr_ptr.i++, rr_len--;

                ce_ptr = NULL;
                rr_flag = RR_FLAG_NM | RR_FLAG_PX /*| RR_FLAG_SL*/;

                while (rr_len >= 4)
                {
                    if (rr_ptr.rr->version != 1)
                    {
#ifndef STAGE1_5
                        if (debug)
                            printf(
	                               "Non-supported version (%d) RockRidge chunk "
	                               "`%c%c'\n", rr_ptr.rr->version,
	                               rr_ptr.rr->signature & 0xFF,
	                               rr_ptr.rr->signature >> 8);
#endif
                    }
                    else
                    {
                        switch (rr_ptr.rr->signature)
                        {
                        case RRMAGIC('R', 'R'):
                          if ( rr_ptr.rr->len >= (4+sizeof(struct RR)))
	                        rr_flag &= rr_ptr.rr->u.rr.flags.l;
                          break;
                        case RRMAGIC('N', 'M'):
                          name = rr_ptr.rr->u.nm.name;
                          name_len = rr_ptr.rr->len - (4+sizeof(struct NM));
                          rr_flag &= ~RR_FLAG_NM;
                          break;
                        case RRMAGIC('P', 'X'):
                          if (rr_ptr.rr->len >= (4+sizeof(struct PX)))
	                        {
	                          file_type = ((rr_ptr.rr->u.px.mode.l & POSIX_S_IFMT)
		                           == POSIX_S_IFREG
		                           ? ISO_REGULAR
		                           : ((rr_ptr.rr->u.px.mode.l & POSIX_S_IFMT)
			                          == POSIX_S_IFDIR
			                          ? ISO_DIRECTORY : ISO_OTHER));
	                          rr_flag &= ~RR_FLAG_PX;
	                        }
                          break;
                        case RRMAGIC('C', 'E'):
                          if (rr_ptr.rr->len >= (4+sizeof(struct CE)))
	                        ce_ptr = rr_ptr.rr;
                          break;
#if 0		            // RockRidge symlinks are not supported yet
                        case RRMAGIC('S', 'L'):
                        {
                        int slen;
                        unsigned char rootflag, prevflag;
                        char *rpnt = NAME_BUF+1024;
                        struct SL_component *slp;

                        slen = rr_ptr.rr->len - (4+1);
                        slp = &rr_ptr.rr->u.sl.link;
                        while (slen > 1)
                          {
                        rootflag = 0;
                        switch (slp->flags.l)
                          {
                          case 0:
	                        memcpy(rpnt, slp->text, slp->len);
	                        rpnt += slp->len;
	                        break;
                          case 4:
	                        *rpnt++ = '.';
	                        /* fallthru */
                          case 2:
	                        *rpnt++ = '.';
	                        break;
                          case 8:
	                        rootflag = 1;
	                        *rpnt++ = '/';
	                        break;
                          default:
	                        printf("Symlink component flag not implemented (%d)\n",
	                           slp->flags.l);
	                        slen = 0;
	                        break;
                          }
                        slen -= slp->len + 2;
                        prevflag = slp->flags.l;
                        slp = (struct SL_component *) ((char *) slp + slp->len + 2);

                        if (slen < 2)
                          {
	                        /*
	                         * If there is another SL record, and this component
	                         * record isn't continued, then add a slash.
	                         */
	                        if ((!rootflag) && (rr_ptr.rr->u.sl.flags.l & 1) && !(prevflag & 1))
	                          *rpnt++='/';
	                        break;
                          }

                        /*
                         * If this component record isn't continued, then append a '/'.
                         */
                        if (!rootflag && !(prevflag & 1))
                          *rpnt++ = '/';
                        }
                        *rpnt++ = '\0';
                        grub_putstr(NAME_BUF+1024);// debug print!
                        }
                        rr_flag &= ~RR_FLAG_SL;
                        break;
#endif
		            	default:
			            break;
                        }
                    }

                    //
                    // There is no more extension we expects...
                    //
                    if (!rr_flag)
                        break;

                    rr_len -= rr_ptr.rr->len;
                    rr_ptr.ptr += rr_ptr.rr->len;
                    if (rr_len < 4 && ce_ptr != NULL)
                    {
                          /* preserve name before loading new extent. */
                          if( RRCONT_BUF <= (unsigned char *)name
                          && (unsigned char *)name < RRCONT_BUF + ISO_SECTOR_SIZE )
                        {
                          memcpy(NAME_BUF, name, name_len);
                          name = NAME_BUF;
                        }
                          rr_ptr.ptr = RRCONT_BUF + ce_ptr->u.ce.offset.l;
                          rr_len = ce_ptr->u.ce.size.l;
                          if (!iso9660_devread(ce_ptr->u.ce.extent.l, 0, ISO_SECTOR_SIZE, RRCONT_BUF))
                        {
                          errnum = 0;	/* this is not fatal. */
                          break;
                        }
                          ce_ptr = NULL;
                    }
                } /* rr_len >= 4 */

                filemax = MAXINT;

                if (name_len >= pathlen
                    && !memcmp(name, dirname, pathlen))
                {
                    if (dirname[pathlen] == '/' || !print_possibilities)
                    {
                        /*
                        *  DIRNAME is directory component of pathname,
                        *  or we are to open a file.
                        */
                        if (pathlen == name_len)
                        {
                            if (dirname[pathlen] == '/')
                            {
                                if (file_type != ISO_DIRECTORY)
                                {
                                    errnum = ERR_BAD_FILETYPE;
                                    return 0;
                                }
                                goto next_dir_level;
                            }
                            if (file_type != ISO_REGULAR)
                            {
                                errnum = ERR_BAD_FILETYPE;
                                return 0;
                            }

                            INODE->file_start = idr->extent.l;
                            filepos = 0;
                            filemax = idr->size.l;
                            return 1;
                        }
                    }
                    else	/* Completion */
                    {
#ifndef STAGE1_5
                        if (print_possibilities > 0)
                            print_possibilities = -print_possibilities;

                        memcpy(NAME_BUF, name, name_len);
                        NAME_BUF[name_len] = '\0';
                        print_a_completion (NAME_BUF);
#endif
                    }
                }
            } /* for */

            size -= ISO_SECTOR_SIZE;
        } /* size>0 */

        if (dirname[pathlen] == '/' || print_possibilities >= 0)
        {
	      errnum = ERR_FILE_NOT_FOUND;
	      return 0;
        }

next_dir_level:
        dirname += pathlen;

    } while (*dirname == '/');

    return 1;
}

int
iso9660_read (char *buf, int len)
{
  int sector, blkoffset, size, ret;

  if (INODE->file_start == 0)
    return 0;

  ret = 0;
  blkoffset = filepos & (ISO_SECTOR_SIZE - 1);
  sector = filepos >> ISO_SECTOR_BITS;
  while (len > 0)
    {
      size = ISO_SECTOR_SIZE - blkoffset;
      if (size > len)
        size = len;

      disk_read_func = disk_read_hook;

      if (!iso9660_devread(INODE->file_start + sector, blkoffset, size, buf))
	return 0;

      disk_read_func = NULL;

      len -= size;
      buf += size;
      ret += size;
      filepos += size;
      sector++;
      blkoffset = 0;
    }

  return ret;
}

#endif /* FSYS_ISO9660 */
